American Indian (AI) reservation populations face numerous chronic stressors. Poverty, unemployment, violence, and accidents are all common, and it has been argued that the combination of historical trauma, inconsistent and disruptive governmental policies, and mandated boarding schools, have rendered many in current reservation populations especially vulnerable to both the impact of everyday chronic stressors, to substance misuse, and to PTSD. Drug use has also been documented among AIs, with AI youth often reporting greater use of drugs and tobacco than many others in the U.S. Only recently have data about the prevalence of drug disorders become available; such data suggest drug disorder rates that are comparable to other populations, but with age trends reflecting that AI youth are at increased risk for lifetime use of both drugs and tobacco compared to their elders suggesting an upward trend in drug disorders among AIs. Thus, the focus of the proposed research on the relationship between chronic stressors and drug use and disorders in this population is particularly timely. The data from the American Indian Service Utilization, Psychiatric Epidemiology; Risk and Protective Factors Project (AI-SUPERPFP) provide a unique opportunity for an epidemiological investigation of stress and drug disorders in an understudied population with a comprehensive assessment of chronic stressors (historical traumas, family history, childhood stressors, traumatic events, chronic strains, frequent lifetime events, and macro level stressors) in combination with standard measures of use and disorder for 9 drugs. The following specific aims guide this work: 1) To characterize and estimate the epidemiology of chronic stressors in these 2 reservation populations; 2) To understand and describe the relationships between chronic stressors, drug use, and DSM-defined drug abuse and dependence in these populations; 3) To investigate and portray the relationships between chronic stressors, drug use and disorders, and co-occurring problems including PTSD, other DSM-defined problems (depressive, anxiety, and alcohol disorders), and violence and antisocial behavior. Within each specific aim, the role of important demographic correlates (e.g., gender, tribe, SES, and age) and personal resources (coping, self-esteem, external locus of control, social support, spirituality, ethnic identity, and treatment history) will be investigated. The American Indian and Alaska Native Programs (AIANP) provide a distinctive multidisciplinary environment in which to conduct this work. The proposed work promises to provide the most comprehensive and focused investigation to date of chronic stressors within Al populations and of the relationship of various stressors with drug use and disorder.